Enhanced corneal permeation of diclofenac through an ophthalmic nanocrystal suspension.

Diclofenac (DCF) is a non-steroidal anti-inflammatory drug (NSAID) with analgesic, anti-inflammatory and antipyretic effects, commonly used to treat painful and chronic inflammatory conditions linked to angiogenesis. It works by inhibiting cyclooxygenase (COX) enzymes and leukocyte migration, reducing prostaglandin synthesis and inflammation. Topically, DCF is used to manage ocular inflammation such as uveitis and keratitis, prevent cystoid macular edema post-surgery, and maintain mydriasis during operations. Clinical studies show it provides anti-inflammatory benefits comparable to dexamethasone but with a lower risk of increasing intraocular pressure. DCF may also help prevent posterior capsule opacification after cataract surgery. This study aimed to enhance DCF ocular delivery using nanocrystals. Stabilized with Poloxamer 188, the nanosuspensions produced monodisperse nanocrystals (∼450 nm) with a negative ζ-potential (-38 mV), significantly improving corneal permeation versus standard formulations. Ex vivo bovine cornea studies confirmed faster and more efficient drug penetration from the nanosuspension compared to a commercial solution. Safety was supported by BCOP, HET-CAM and cell viability assays, all showing no irritation. Corneal hydration remained stable, indicating low irritation potential. In summary, the developed nanosuspensions offer a promising strategy for improving DCF ocular delivery and therapeutic efficacy. Further clinical studies are needed to confirm long-term safety and effectiveness in humans.